Transient Fluid Mechanics LaboratoryTechnion – Israel Institute of Technology

Research

Two threads run through everything we do: shock waves and compressible flow on one side, multiphase flows made visible by refractive index matching on the other. Both depend on time-resolved measurements of fast events, and on building the experiments that make those measurements possible.

Compressible flows and shock waves

How moving shock waves reflect, diffract and recover when they meet area changes, constrictions and porous barriers inside ducts, studied in our automated shock tube with high-speed schlieren imaging and large-eddy simulation.

  • Shock waves through abrupt area changes

    How a normal shock recovers after an abrupt expansion or contraction in a duct, combining shock-tube experiments, large-eddy simulation and geometrical shock dynamics.

  • Shock interaction with local constrictions

    Systematic experiments and simulations of shocks passing through short constrictions, from abrupt rectangular blocks to smooth sinusoidal narrowings.

  • Shock waves and porous media

    Stiff porous media act as a first-order low-pass filter on the pressure pulse that follows a shock, which lets us predict the load on a protected wall without new experiments.

Multiphase and index-matched flows

Time-resolved, three-dimensional measurements of solids, bubbles and droplets in liquids, made possible by matching the refractive index of the fluid to the walls and particles so that four high-speed cameras can see the whole flow at once.

  • Inertial solids in high-speed pipe flow

    Time-resolved tomographic imaging in an index-matched pipe reveals how inertial spheres move through high Reynolds number flow and area changes.

  • Turbulence in round pipes across area changes

    Stereo and tomographic PIV of turbulent pipe flow through abrupt and gradual expansions and contractions, a simple geometry that is notoriously hard to image.

  • Tomo-PTV of buoyancy driven spheres

    How we measure the forces on a freely rising sphere that is optically invisible: index matching, a detection method built on the flow's fingerprints, and a reconstruction that respects the moving body.

  • Inception of attached cavitation

    Why attached cavitation on curved surfaces is insensitive to free-stream nuclei: microbubbles trapped near the wall keep seeding new events.

  • Oil–water separation and thin water films

    Water droplets crossing an oil–water interface are wrapped in a film that persists thousands of times longer than the crossing itself, with consequences for oil-spill dynamics.